Washington Redskins rookie running back Derrius Guice is out for the season after tearing the ACL in his left knee, a significant blow to the ground game.

Guice was injured in Washington's preseason opener at New England on Thursday night and could be seen on the sideline with ice on his knee. The team announced the prognosis Friday following an MRI, saying Guice should make a full recovery and be ready to play in 2019.

Guice was expected to be the Redskins' starter after they selected him 59th overall in the draft. The LSU product was considered a first-round prospect and fell amid reports of character concerns before being taken late in the second.

"Grabbing him in the second round was obviously a great treat for us, but character was never a concern," coach Jay Gruden said recently, pointing to injuries and the quality of running backs as reasons for Guice falling in the draft. "He's been great, never been late, attentive, great attitude, always happy, happy-go-lucky and fun to be around, quite frankly."

Washington averaged 90.5 yards rushing last season, fifth-worst in the NFL. Injuries to Week 1 starter Rob Kelley and prolific third-down back Chris Thompson contributed to that, and Guice was expected to be a major part of solving the problem.

"He was supposed to be a first-round pick," Thompson said earlier in training camp. "He's one of those guys we're expecting a lot out of him. ... They're not expecting him to come here and have a 500-yard season. For him, I want 1,000-plus. I want that for him."

In camp, Guice had been splitting first-team carries with Kelley and Samaje Perine. Gruden has said there's competition for the No. 1 job along with Thompson, who's coming back from a broken fibula.

"Had a tough time tryna hold back the tears this morning when I got the news," Thompson tweeted after Guice's injury was revealed. "We had something great going in our room but you know the squad got you every step of the way bro. Heal up and get ready to take over the league next year."

The competition is now wide open after Guice's season-ending injury. Kelley, a 2016 undrafted free agent who began last season as the starter, has gone from "Fat Rob" to "Fit Rob" and should now be considered the front-runner.

"I just make sure I go out there and I make a few plays that the catch the coaches' eyes and stuff like that and put myself in a great position," Kelley said. "At the end of the day, I can't pick who wins and lose the competition; it's up to the coaches and stuff like that. So, control what you can control."